I just finished my Jeep conversion, and thought I would share. I know there are others who have shown how to do it, but I thought I would walk everyone through my process which was quite simple and yielded perfect results.
With that stated, here we go...
First of all, you need the Jada 1/43 scale Jeep. You can typically find these on Ebay, but may have to come from China depending upon current auctions. Even thought the body is wider, the Jeep has pretty much an identical footprint of the OEM one. Also, you will want to hot glue the doors shut or use some other method to secure them. I opened the door, lined the jam with hot glue, then held it closed for several seconds while the glue firmed.
IMG_4742 (resized).JPGIMG_4743 (resized).JPG
To remove the Jeep FIRST REMOVE THE BALLS then lift the playfield and you'll use a 3/32" hex wrench to loosen the locks screw on the shaft (pay attention to the orientation of the metal tab as this is what triggers the optos). When removing this be sure to hold onto the Jeep on the topside or it may slide out and damage something. Also, there are 3 washers on the topside including a ball bearing washer. If you lose or break this, your jeep will not rotate properly.
Carefully pull out the jeep assembly from the topside, again paying careful attention to catch the 3 washers. When removed set the washers aside, remove the 4 screws holding the jeep to the shaft plate, and also remove the nut & washer holding the newton ball on the shaft to get it out of the way.
Now you will want to test position the jeep on the plate so that you know where it needs to sit. This is important for both balance and clearance from the helix when the Jeep is rotating. The proper alignment is where the washer from the center posts is touching the extended plastic around the rear axle of jeep.
Turn the Jeep over and position the plate where the extension is towards the rear of the model. The plate will need to be centered horizontally with the two rear holes straddling the raised piece, and again the washer should be touching the base of the raised rear axle plastic.
Holding the bracket in place you will want to drill a pilot hole for one of the back screws (do not drill all 4 holes at once. Do them one at a time to ensure proper alignment). I used a 1/16" bit for the pilot holes which worked perfect with the original screws. Once a rear hole is drilled, then insert a screw an tighten to where it is just snug. Don't over do this or you will strip the plastic.
Next, drill the pilot hole for the screw that is catty-corner to the first one you did (e.g. if you started with the back right, next will be the front left). When doing the front screws don't over tighten them. You want the metal plate to be parallel to the bottom of the Jeep instead of slanting towards the front. Ideally you would use spacers on the front (I didn't have any, but will probably retrofit them later).
Repeat the process with the remaining two screws.
When finished, the underside of the assembly should look like this.
Reattach the newton ball to the shaft, put the 3 washer assembly back on the shaft, then insert the shaft into the hole on the topside of the playfield. On the bottom side of the playfield slide the collar back on paying attention to the orientation, then tighten the set screw. You will want to leave about 1 mm of clearance between the collar and the bushing, otherwise the Jeep will not rotate freely. However, don't make this gap too large or the metal tab may scrape the lower optos causing less than ideal rotation or worse yet hit the side of the optos and not make the full rotation.
Lower the playfield and rotate the Jeep both ways by hand and even by manually slamming the stationary ball with a pinball. You should have a nice smooth full rotation with good clearance at both front and rear.
IMG_4746 (resized).JPGIMG_4745 (resized).JPG
Finally, add all of the balls back into the game and play a few practice balls. When you are happy with your installation replace the glass and your ready to enjoy your new Jeep!
I also wanted to mention that while I've not done it yet I may paint the metal bracket that sticks out from behind the jeep black in order to make it less noticeable.
Another thought is to put a dab of glue where the screws meet the underside plastic of the Jeep to help prevent them from working loose.